Collection of Process Data Using In-Situ Sensors

ABSTRACT

A system is provided for collecting data during vacuum molding of a composite part using a mold including an air tight, flexible membrane sealed to a tool. The system comprises a plurality of MEMS sensors coupled with the interior of the mold at different locations over the part. Each of the sensors produces signals related to a process parameter, such as pressure within the bag, that is sensed at the location of the sensor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to U.S. patent application Ser. No.12/041,832, filed Mar. 4, 2008, the entire contents of which areincorporated by reference herein.

TECHNICAL FIELD

This disclosure generally relates to techniques for collectingindustrial process data, and deals more particularly with a system andmethod using in-situ sensors to collect data during composite moldingand curing processes, especially those performed within an autoclave.

BACKGROUND

In one form of vacuum bag molding, prepreg sheet material is laid up ona mold tool. A flexible vacuum bag is then placed over the layup and theedges of the bag are sealed to the mold tool. The mold tool may beheated and a vacuum is drawn within the bag that results in thesurrounding atmospheric pressure applying pressure to the layup. In somecases, the mold is placed in an autoclave that applies both heat andexternal pressure, adding to the force of the atmospheric pressureapplied to the bag. It may be desirable to measure the pressure that isapplied at various locations over the layup since these local pressuresmay have an affect on the porosity, and thus the quality of the curedcomposite part.

Current systems for monitoring molding pressures, particularly thosewhere the layup is processed in an autoclave, employ one or more vacuumhoses that are connected between the autoclave shell or wall, and thevacuum bag. The hoses are connected to pressure/vacuum transducers whichare located outside of the autoclave. This technique measures onlyvacuum bag pressure, and does not sense the hydrostatic pressure of theresin which can important in monitoring and controlling the process.Furthermore, because the vacuum hoses are relatively bulky andexpensive, only a limited number of transducers are used to monitor theprocess, thus limiting the amount of information that can be gathered.Moreover, the use of long hoses to connect remote transducers to thelayup may affect measurements in unpredictable ways.

Accordingly, there is need for a system for collecting vacuum andpressure data that eliminates the need for long connecting hoses byusing multiple in-situ sensors located on or immediately near the vacuumbag to collect the data. Further, there is a need for a system of thetype mentioned above that is highly flexible and allows measurement ofat least some parameters before a part layup is loaded into theautoclave and/or after the part layup has been removed from theautoclave.

SUMMARY

The disclosed embodiments employ in-situ, MEMS-based sensors to monitorpressures and/or vacuum in vacuum bag molding processes, including thoseperformed within an autoclave. For example, the MEMS-based sensors maybe used to sense the pressure applied by an autoclave to various areasof a part layup in order to assess the areal uniformity of the appliedpressure which may affect, for example and without limitation, theporosity of the finished part. The embodiments reduce or eliminate theneed for long and cumbersome hoses and couplings previously required toconnect remote sensors with the vacuum bag. The illustrated embodimentsalso provide a low cost, disposable system for sensing pressures/vacuumat multiple locations over the vacuum bag where it may be important tomonitor vacuum and/or resin hydrostatic pressure.

The use of MEMS-based sensors allows measurement of vacuum or pressureat exact locations either on the tool side of the layup or on the bagside. The sensors can differentiate between resin hydrostatic pressure,vacuum levels and autoclave pressure. By sensing these multipleparameters at differing locations, the system can provide earlydetection of leaks and their exact location, which facilitatesdiagnostics.

According to one disclosed embodiment, a system is provided forcollecting data during vacuum bag molding of a composite part using amold including a flexible membrane sealed to a tool. The systemcomprises a plurality of pressure sensors coupled with the interior ofthe mold at different locations over the part, wherein each of thesensors produces signals related to the pressure applied to the part atthe location of the sensor. The system may further comprise a processorlocated in the area of the mold for collecting and processing the sensorsignals. At least certain of the sensors may be attached to the exteriorside of the membrane, overlying openings in the membrane that place theinterior of the mold in communication with the sensors. The sensors mayinclude a substrate and a MEMS pressure sensor mounted on the substrate.At least one of the sensors may be mounted directly on the tool and maysense either a vacuum pressure or a fluid pressure within the mold.

According to another disclosed embodiment, apparatus is provided forvacuum bag molding a composite part layup, comprising: a mold includinga mold tool and a vacuum bag wherein the vacuum bag covers the layup andis sealed to the mold tool; at least one sensor on the mold forgenerating a signal representing pressure applied to the part at thelocation of the sensor; and, means for processing the sensor signal. Themold tool may include an interior wall defining a mold cavity having arecess therein, and the sensor may be mounted within the recess in orderto sense a pressure within the mold cavity in the area of the recess.

According to another embodiment, a system is provided for measuring thepressure applied to a vacuum bagged composite layup molded and curedinside an autoclave, comprising: a plurality of pressure sensors eachcoupled with the interior of the bag and sensing the pressure applied tothe layup at the location of the sensor; and, at least one sensor insidethe autoclave for sensing the pressure inside the autoclave. At leastone of the sensors senses a vacuum pressure within the bag, and at leastone of the sensors may sense a fluid pressure within the bag.

According a disclosed method embodiment, measuring process parameters ina vacuum bag molding operation comprises: sensing the value of at leastone parameter inside the bag at each of a plurality of locations overthe bag while a vacuum is drawn in the bag; and, collecting the sensedvalues. The method may further comprise forming an opening in the bag ateach of the locations, and attaching the plurality of sensors to thevacuum bag respectively over lying the openings, wherein sensing thevalues of the parameter is performed using the sensors. Collecting thesensed values may include wirelessly transmitting the sensed values to acollection site.

According to another disclosed embodiment, a method is provided formonitoring the pressure applied to a vacuum bag composite layupprocessed inside an autoclave, comprising: coupling each of a pluralityof pressure sensors with the interior of the bag at different sensinglocations over the layup; using the sensors to generate a set signalsrespectively representing the pressure applied to the layup at thesensing location; and, collecting the signals at a location within theautoclave near the layup. Coupling the sensors to the interior of thebag may include forming an opening in the bag at each of the sensinglocations, and attaching one of the sensors to the bag overlying one ofthe openings.

Embodiments of the disclosure satisfy the need for a system formeasuring pressures and/or vacuum a vacuum bag molding operation carriedout in an autoclave which eliminates the need for bulky hoses, uses lowcost in-situ sensors, and allows process monitoring before the layup isplaced in the autoclave, and/or after it has been removed from theautoclave.

Other features, benefits and advantages of the disclosed embodimentswill become apparent from the following description of embodiments, whenviewed in accordance with the attached drawings and appended claims.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is a side sectional view of a vacuum bag mold assembly havingin-situ sensors for monitoring pressure/vacuum, before a vacuum is drawnin the bag.

FIG. 2 is a top view of the vacuum bag molding assembly shown in FIG. 1,and also showing a control module.

FIG. 3 is a combined block and diagrammatic view of a system forcollecting and processing sensor signals.

FIG. 4 is a perspective view of a MEMS pressure sensor.

FIG. 5 is a plot showing the electrical output of the MEMs sensor shownin FIG. 4 as a function of sensed pressure.

FIG. 6 is a sectional group view of a MEMS pressure sensor attached to avacuum bag.

FIG. 7 is a sectional view showing a MEMS pressure sensor attached to avacuum bag by a gland.

FIG. 8 is a sectional view showing a MEMs pressure sensor mounted withina recess in a mold tool.

FIG. 9 is a sectional view showing a MEMS sensor used to sensehydrostatic resin pressure in a vacuum bag mold assembly.

FIG. 10 is a view similar to FIG. 9 but showing a MEMS sensor used tomeasure vacuum pressure.

FIG. 11 is a sectional view showing MEMS pressure sensors embeddedwithin a caul plate.

FIG. 12 is a sectional view showing MEMS pressure sensors interposedbetween a vacuum bag and a layup.

FIG. 13 is a sectional view showing MEMS pressure sensors embeddedwithin a layup.

FIG. 14 is a flow diagram showing a method of sensing and collectingprocess data using the in-situ MEMS sensors.

FIG. 15 is a flow diagram of aircraft production and servicemethodology.

FIG. 16 is a block diagram of an aircraft.

DETAILED DESCRIPTION

Referring first to FIGS. 1 and 2, a vacuum bag mold assembly generallyindicated by the numeral 20 broadly comprises a mold tool 24 used tomold a composite part layup 22 which may comprise, for example andwithout limitation, multiple plies of a fiber reinforced polymer resin.Pressure is applied to the layup 22 by a flexible membrane such as avacuum bag 26 which may comprise, for example and without limitation, aflexible film such as PVA, nylon, Mylar® or polyethylene. The vacuum bag26 is attached to the mold tool 24 by a seal 28 which typically maycomprise a sticky, putty-like bag sealant that creates a substantiallyvacuum tight enclosure surrounding the layup 22. Although not shown inthe drawings, a bleeder ply, a release film, a caul plate and a breathermay be introduced between the layup 22 and the bag 26. A vacuum systemand related hardware (not shown) may be coupled with the mold assembly20 to draw a vacuum within the vacuum bag 26. Additionally, an optionalresin infusion system (not shown) may be coupled with the mold assembly20 in applications where the layup 22 comprises a dry perform requiringthe infusion of resin.

In FIG. 1, the bag 26 is shown as being loosely positioned over thelayup 22 before a vacuum is drawn within the bag 26. The vacuum drawnwithin the bag 26 results in the surrounding atmospheric pressurepressing the bag 26 against the layup 22 which reacts against the moldtool 24 to eliminate voids and force excess resin from the layup 22. Thecompaction pressure created by the vacuum further results inconcentrating the reinforcing fibers (not shown) in the layup 22 andremoving entrapped air to reduce voids and achieve substantially uniformlamination of the layup 22.

For any of various reasons, the pressure applied by the bag 26 to thelayup 22 may not be uniform across the entire surface of the layup 22contacted by the bag 26. In accordance with one disclosed embodiment, aplurality of vacuum pressure sensors 30 may be attached to exterior side33 of the bag 26 at those locations where vacuum pressure is to bemonitored. As will be discussed later in more detail, the bag 26includes openings (not shown) at the location of the sensor 30 whichplaces sensor 30 in communication with the interior of the bag 26.

One or more additional pressure sensors 30 may also be incorporated intothe mold tool 24, beneath the layup 22 in order to sense either vacuumpressure or hydrostatic resin pressure at areas on the layup 22 otherthan those contacted by the bag 26. Sensors 30 generate signalsrepresenting the sensed pressures which are output on electrical leadlines 32 connected to a control module 45 located near the mold 20. Itmay also be possible to employ sensors 30 that incorporate miniaturized,wireless transmitters (not shown) to send the signals wirelessly to thecontrol module 45. In the illustrated example, the mold 20 may be placedin an autoclave 25 or similar pressure vessel where the layup issubjected to elevated pressure and temperature. The control module 45may be located outside the autoclave 25, alternatively however, as willbe described below, the control 25 module may be located inside theautoclave 25. The pressure applied to the layup 26 by the autoclave 25supplements the atmospheric pressure applied to the layup 22 as a resultof the vacuum within the bag 26. One or more additional pressure sensors30 a may be placed outside of the vacuum bag 26 in order to sense thepressure within the autoclave 25 that may be applied to the vacuum bag26. In the illustrated example, a pressure sensor 30 a is placed on anedge of the mold tool 24 and is connected by a lead 22 to the controlmodule 45.

Referring now to FIG. 3, the control module 45 may broadly include awireless transmitter 36, a microcontroller 40 and a power source 44. Thewireless transmitter 36 may comprise a conventional RF transmitter thatwirelessly transmits the sensor data from the transmitting antenna 38.Other types of wireless technology may be employed such as, for example,without limitation, infrared transmission. Alternatively, the controlmodule 45 may be located in a benign environment outside the autoclave25 where it is connected to the sensors 30 by a wire pass-through 59 inthe autoclave wall 25 a.

The microcontroller 40 may comprise a commercially available processorthat collects and processes the signals received from sensors 30, 30 a,and manages other functions of the control module 45, such as thetransmission of data by the transmitter 36. Optional data storage 42 maybe provided in the control module 45 for storing the sensor data so thatit may be downloaded after layup processing is complete. The powersource 44 may comprise a battery, or a source of AC power that isconverted to suitable DC power for operating the wireless transmitter 36and the microcontroller 40. The wireless transmitter 36 includes atransmitting antenna 38 that transmits sensor data signals (i.e.measurements) to a receiving antenna 47 that may be located inside theautoclave 25. A wireless receiver 49 located outside of the autoclave 25may be connected by wiring 59 that passes through a wall 25 a of theautoclave 25 and connected to the receiving antenna 47. The wirelessreceiver 49 may be connected to a data collection/processing system 51that collects and processes the transmitted sensor data. For example,the data collection/processing system 51 may include one or more of adata logger 53, computer 55 and/or a display 57 that displays the datafor operator observation/use.

Although not shown in the drawings, the control module 45 may be placedin a protective container of the type more fully described in U.S.patent application Ser. No. 12/041,832 filed Mar. 4, 2008. Theprotective container protects the components of the control module 45from the heat and pressure present within the autoclave 25.

Referring now to FIGS. 4 and 5, the sensors 30, 30 a may each comprise aMEMS (micro-electromechanical system) pressure sensor device 46 as thosecommercially available from Intersema Sensoric SA in Bevaix,Switzerland. The MEMS device 46 described above comprises amicro-machined silicon part (not shown) and Pyrex® glass (not shown).Piezo resistances (not shown) are mounted on top of the silicon partjust above a sensor membrane (not shown). The membrane may be only a fewmicrometers thick and deflects, depending on the pressure differenceexisting between its two sides. The MEMS device 46 in turn is mounted ona ceramic or other suitable type of substrate 48 to which the leads 32are connected. A ring 50 mounted on the substrate 48 forms a protectivewall around the MEMS device 46, and may be partially filled with anencapsulation (not shown) that protectively overlies the MEMS device 46.As shown in FIG. 5, the output of the MEMS device 46 indicated at 52 isfunction of sensed pressure (vacuum or fluid) and is relatively linear.

Attention is now directed to FIG. 6 which shows a pressure sensor 30attached to the outer face 33 of the vacuum bag 26. A through-holeopening 56 is formed in the bag 26, as by puncturing the bag 26, at thelocation where the sensor 30 is to be attached. The pressure sensor 30is positioned such that the pressure membrane (not shown) in MEMS device46 overlies the opening 56, thus placing the MEMS device 46 incommunication with the interior of the bag 26. A vacuum bag sealant tape34 seals the sensor 30 to the bag 26, creating a vacuum-tight sealaround the opening 56. A suitable adhesive tape 54 may be placed overthe sensor 30 and adhered to the outer face 33 of the bag 26 in order tofurther hold the sensor 30 in place, and protect the relativelythin-gauge electrical leads 32. The dimensions of the tape 54 should begreat enough to supplement the vacuum tight seal completely around thesensor 30. The electrical leads 32 may be stress-relieved on the bag 26by the tape 54. The electrical leads 32 may include connectors 58 usedto connect the sensors 30 with the control module 35.

Referring to FIG. 7, the sensors 30 may be relatively bulky due to theuse of the mounting substrate 48 and the ring 50. The MEMS device 46 maybe incorporated (partially or fully embedded) directly into a layer 31of breather material, which is used to convey the vacuum uniformlyunderneath the vacuum bag 26. The MEMS device 46 is packaged in a patchof the layer 31 of the breather material, which in turn is placeddirectly into the breather (not shown) covering the plies of prepregforming the layup 22.

Referring now to FIG. 8, a sensor 30 may be mounted within one or morerecesses 43 formed in the interior face 67 of the mold tool 24. Incontrast to the previously discussed sensors 30 attached to the bag 26which sense pressure on the top side of the layup 22, sensor 30 sensesthe pressure or vacuum that exists between the layup 22 and the moldtool 24. A via 60 may be formed in the mold tool 24 in order to allowconnection of an electrical lead 32 to the MEMS device 46.

FIG. 9 illustrates in more detail a pressure sensor mounted within arecess 43 in the mold tool 24 that functions to sense the hydrostaticpressure of resin flowing through the layup 22. In this example, thering 50 is mounted within a through hole opening 62, with the MEMSdevice 46 facing the layup 22. The open area 62 above the MEMS device 46may be filled with a fluid pressure transmitting gel 69 which transfersthe hydrostatic resin pressure from the layup 22 to the MEMS device 46where it is measured. The substrate 48 may be secured to the bottom ofthe mold tool 24 to hold the sensor 30 in place.

FIG. 10 is a view similar to FIG. 9, but shows the open area 62 abovethe MEMS device 46 as being only partially filled with gel 69, and athin plate 64 or porous media interposed between the end of the ring 50and the bottom of the layup 22. The open area 62 a beneath the plate 64is subjected to vacuum pressure whose magnitude is sensed by the MEMSdevice 46.

FIG. 11 illustrates a vacuum bag mold assembly 20 a in which a layup 22is compressed between a first tool 24 and a second tool in the form of acaul plate 71 that is covered by a vacuum bag 26. The caul plate 71 maybe semi-flexible or rigid and has a thickness “t” greater than thethickness of the sensors 30. In this embodiment, the MEMS sensors 30 areembedded into the bottom face 77 of the caul plate 71, facing the layup22. Sensor wires 32 pass through vias 60 in the caul plate 71 andpass-through openings (not shown) in the bag 26. Tape 54 or a similarsealing medium overlies and seals the pass-through openings in the bag26.

Another embodiment 20 b of a vacuum bag mold assembly is illustrated inFIG. 12 in which the MEMS pressure sensors 30 are placed inside the bag26, interposed between the bag 26 and the layup 22. The MEMS sensors 30may be adhered to the inside face 81 of the bag 26, or placed on top ofthe layup 22 and then covered by the bag 26 during assembly of the moldassembly 20 b. During the assembly process, the sensor wires 32 may beused to pierce the bag 26 in order to form wire pass-through openings 56in the bag. Tape 54 or a similar sealing medium may be used to seal thepass-through openings 56.

FIG. 13 illustrates still another embodiment 20 c of a vacuum bag moldassembly in which the MEMS sensors 30 are embedded within the layup 22.Specifically, the sensors 30 may be embedded within either laminatelayers 73 or a core 75, or both. In the illustrated example, the core 75comprises a honeycomb, but the core 75 may comprise other materials suchas, without limitation, a foam or other materials. Also, the sensors 30may be embedded in any of various inserts (not shown) that may besandwiched between the laminate layers 73. Vias 83 may be formed in thecore 75 and/or laminate layers 73 to allow the sensors wires 32 to berouted to and through the bag 26. As in the previously describedembodiments, tape 26 or similar means may be used to seal wirepass-through openings in the bag 26.

It should be noted here that the sensors 30 may also be mounted on or inothers areas covered by or contacting the bag 26, such as withoutlimitation a breather (not shown), a peel ply (not shown), a seal 28(FIG. 1), ports (not shown) and outlets (not shown).

Attention is now directed to FIG. 14 which shows, in simplified form,the steps of a method for measuring vacuum/pressures using the in-situsensors 30 previously described. Beginning at 70, the layup 22 is formedon the mold tool 24. The vacuum sensors 30 may be applied at this pointin the process. Then at 72, the bag 26, which may typically include arelease film (not shown), a breather (not shown) and a type of caulplate (not shown), is sealed to the mold tool 24. At 74, the throughopenings 56 are formed in the bag 26 at the locations where it isdesired to sense the vacuum pressure applied to the layup 22. Aspreviously mentioned, the openings 56 may be formed by simply puncturingthe bag 26 using a suitable tool (not shown) or the sensor wires 32.Next, at 76, the sensors 30 are installed in any of the locationspreviously described. At step 78, the sensor wires 32 are connected tothe control module 45. At this point, the sensors 30 are functional andmay be monitored if desired, as shown at 93. The vacuum integrity of thebag seal may be checked at 82 by shutting off the vacuum source andmeasuring how fast vacuum is lost by the bag 26. The in-situ sensors 30facilitate this test by measuring and recording vacuum and time data,and may reveal the proximity of any leak in the bag system. If the bagfails the leak test at 82, it is repaired at 83.

At 80, the vacuum bag mold assembly 20 is placed inside the autoclave25, following which, at 82, a vacuum is again drawn in the vacuum bag26. The sensor data collected and processed by the microcontroller 40may either be stored in the data storage 42, wirelessly transmitted at84, or wired directly through the autoclave wall 25 a, as describedabove so that the sensor data is received outside of the autoclave asindicated at 88. The sensor data may be logged at 92 and the processesare adjusted, as required. A second vacuum integrity check may then beroutinely performed at 85. The vacuum sensors 30 facilitate this leaktest by allowing the measurement of vacuum at a plurality of locations,thus yielding diagnostic information if any leaks are identified. If thebag 26 fails the second leak test 85, the pressure in the bag 26 isreleased and the bag 26 is repaired at 87. At step 86, pressure in theautoclave 25 is increased and the sensors continue to transmit data at93.

The MEMS-based sensors 30 are relatively inexpensive and therefore canbe discarded after a single use, allowing a fresh set of sensors to beused in processing each layup. Moreover, because the MEMS-based sensors30 are both small and inexpensive, they can be deployed in large numberswhere it is desirable to sense pressure at numerous locations on arelatively large layup, such as a fuselage barrel section for aircraft.

In one typical implementation of the disclosed embodiments, the MEMSsensors 30, 30 a may sense vacuum from about −25 in Hg, up to a positivepressure of about 174 PSI, depending upon the particular sensor design.The MEMS-based sensors 30, 30 a may be relatively small in size,measuring from, for example and without limitation, about 0.25×0.25inches for the overall package. The MEMS device 46 itself isconsiderably smaller, offering a diversity of alternate applications.

Embodiments of the disclosure may find use in a variety of potentialapplications, particularly in the transportation industry, including forexample, aerospace, marine and automotive applications. Thus, referringnow to FIGS. 15 and 16, embodiments of the disclosure may be used in thecontext of an aircraft manufacturing and service method 94 as shown inFIG. 15 and an aircraft 96 as shown in FIG. 16. Aircraft applications ofthe disclosed embodiments may include, for example, without limitation,composite stiffened members such as fuselage skins, wing skins, controlsurfaces, hatches, floor panels, door panels, access panels andempennages, to name a few. During pre-production, exemplary method 94may include specification and design 98 of the aircraft 96 and materialprocurement 100. During production, component and subassemblymanufacturing 102 and system integration 104 of the aircraft 96 takesplace. Thereafter, the aircraft 96 may go through certification anddelivery 106 in order to be placed in service 108. While in service by acustomer, the aircraft 96 is scheduled for routine maintenance andservice 110 (which may also include modification, reconfiguration,refurbishment, and so on).

Each of the processes of method 94 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 16, the aircraft 96 produced by exemplary method 94 mayinclude an airframe 112 with a plurality of systems 114 and an interior116. Examples of high-level systems 114 include one or more of apropulsion system 118, an electrical system 120, a hydraulic system 122,and an environmental system 124. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of thedisclosure may be applied to other industries, such as the marine andautomotive industries.

Systems and methods embodied herein may be employed during any one ormore of the stages of the production and service method 94. For example,components or subassemblies corresponding to production process 94 maybe fabricated or manufactured in a manner similar to components orsubassemblies produced while the aircraft 96 is in service. Also, one ormore apparatus embodiments, method embodiments, or a combination thereofmay be utilized during the production stages 102 and 104, for example,by substantially expediting assembly of or reducing the cost of anaircraft 96. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft96 is in service, for example and without limitation, to maintenance,repair of composite structure, and service 110.

Although the embodiments of this disclosure have been described withrespect to certain exemplary embodiments, it is to be understood thatthe specific embodiments are for purposes of illustration and notlimitation, as other variations will occur to those of skill in the art.For example, while the embodiments have been illustrated in connectionwith collecting pressure/vacuum data for a vacuum bag molding operationcarried out within an autoclave, the data collection system and methodmay also be used to collect the data where the operation is notperformed within an autoclave.

1-25. (canceled)
 26. A method of molding a composite layup inside anautoclave, comprising: using a plurality of openings at differingmeasurement locations in a vacuum bag inside the autoclave; using vacuumpressure sensors attached to the bag respectively overlying theopenings, the vacuum pressure sensors individually including a MEMSdevice associated with a ring and an open area within the ring onlypartially filled with pressure transmitting gel; using the vacuumpressure sensors to measure the vacuum within the bag at the measurementlocations through the gel of the individual vacuum pressure sensors;coupling a fluid pressure sensor with the interior of the bag, the fluidpressure sensor including a MEMS device associated with a ring and anopen area within the ring filled with pressure transmitting gel;measuring a fluid pressure inside the bag through the gel of the fluidpressure sensor; and collecting the measured vacuum pressures and themeasured fluid pressure at a location adjacent the composite layup. 27.The method of claim 26 further comprising the step of sending themeasured vacuum pressures and the measured fluid pressure by a wirelesstransmitter.
 28. The method of claim 26 wherein the location adjacentthe composite layup comprises a location inside the autoclave.
 29. Themethod of claim 26 further comprising: using a plurality of additionalsensors at different locations over the composite layup other thanattached to the bag; and collecting additional measured pressures, themeasured vacuum pressures, and the measured fluid pressure using aprocessor in communication with at least one of the plurality ofadditional sensors, the sensors attached to the bag, and the fluidpressure sensor.
 30. The method of claim 29 wherein at least one of theplurality of additional sensors is at least partially embedded within atleast one of a mold tool, a caul, a breather, a peel ply, a seal, andthe composite layup.
 31. The method of claim 29 wherein at least one ofthe plurality of additional sensors is configured to be positionedbetween the vacuum bag and the composite layup.
 32. The method of claim29 wherein at least one of the plurality of additional sensors isconfigured to be embedded within the composite layup.
 33. A system formolding a composite layup inside an autoclave, comprising: a mold tool;a vacuum bag sealed to the mold tool and having a plurality of openingstherein at different sensing locations on the vacuum bag; a plurality offirst MEMS vacuum pressure sensors attached to the vacuum bag andrespectively coupled through the openings to the interior of the vacuumbag; at least one opening in the mold tool; a second pressure sensormounted within the opening in the mold tool and configured to senseeither a vacuum pressure or a fluid pressure inside the mold; and aprocessor configured to be placed inside the autoclave and to collectand process the pressures sensed by the first and second sensors. 34.The system of claim 33 wherein the processor further comprises awireless transmitter configured to wirelessly transmit sensor data. 35.The system of claim 33 further comprising at least one additional sensorat least partially embedded within at least one of a caul, a breather, apeel ply, a seal, and the composite layup.
 36. The system of claim 33further comprising at least one additional sensor disposed inside themold, positioned between the vacuum bag and the composite layup.
 37. Thesystem of claim 33 further comprising at least one additional sensorembedded within the composite layup.
 38. An apparatus for molding acomposite layup, comprising: a mold including a mold tool and a vacuumbag configured to cover the composite layup, the mold tool including abreather; at least one sensor embedded in the breather and configured togenerate a signal representing a parameter sensed at the location of thesensor; and a processor located in the area of the mold and configuredto collect and process the sensor signals.
 39. The apparatus of claim 38further comprising at least one additional sensor at least partiallyembedded within a caul.
 40. The apparatus of claim 38 further comprisingat least one additional sensor at least partially embedded within a peelply.
 41. The apparatus of claim 38 further comprising at least oneadditional sensor at least partially embedded within a seal.
 42. Theapparatus of claim 38 further comprising at least one additional sensorat least partially embedded within the composite layup.
 43. Theapparatus of claim 38 further comprising at least one additional sensordisposed inside the mold and configured to be positioned between thevacuum bag and the composite layup.
 44. The apparatus of claim 38further comprising at least one additional sensor, wherein the mold toolcomprises an interior wall defining a mold cavity and having an openingtherein, wherein the additional sensor is mounted within the opening andsenses a pressure within the mold cavity in an area of the opening. 45.The apparatus of claim 38 further comprising a plurality of additionalsensors on the mold, wherein: each of the plurality of sensors generatesa signal representing a pressure inside the mold at a location of thesensor; at least two of the plurality of sensors are attached to anexterior side of the vacuum bag; and the vacuum bag includes at leasttwo openings therein respectively placing the interior of the vacuum bagin communication with a corresponding at least two of the sensors.